1. Field of the Invention
The present general inventive concept relates to a signal output device of a high definition multimedia interface (HDMI) device and a method thereof to simultaneously transmit a digital audio and video signal, and more particularly, to a signal output device of an HDMI device and a method thereof, which can automatically determine the type of a HDMI cable to display an optimal screen on a display device such as a television set.
2. Description of the Related Art
Recently, digital versatile discs (hereinafter, referred to as DVDs) are widely used as a recording medium for recording/reproducing a high-definition video signal and a high-definition audio signal. In addition, a digital video display device (for example, a digital satellite broadcasting device) capable of displaying a high-definition video signal and a high-resolution digital television set capable of displaying a high-definition digital video signal of a DVD are widely used.
Accordingly, a variety of DVD apparatuses are connected to a digital TV set for recording/reproducing video signals on/from the DVDs (for example, DVD players, DVD recorders or the like) to a digital TV set. A digital visual interface (DVI) device or an HDMI device is used as a digital interface device for transmitting data between the devices.
The HDMI is a multimedia interface for transmitting an uncompressed full digital audio and video signal through a single cable, which provides an interface between a source device, such as an audio/video source, a set top box (hereinafter, referred to as a STB) or a DVD player, and a sync device such as a monitor or a digital TV set.
An apparatus for transmitting an audio and video signal to the sync device such as the digital TV set, using the digital interface device, such as the HDMI device, is referred to as a digital interface apparatus. The digital interface apparatus includes a set top box (STB), a VTR, and a game machine as well as a variety of DVD apparatuses.
Korean Laid-Open Patent Publication No. 2004-0081776 discloses an example of connecting a set top box, which is a source device, and a display device, which is a sync device, through an HDMI cable and transmitting video and audio data.
However, in a digital interface device, such as the HDMI device, disclosed in the above-described publication, a user cannot determine the type of the HDMI cable when the source device and the sync device are connected through the HDMI cable. Accordingly, when the HDMI cable cannot support a current output resolution, the display device, which is the sync device, cannot output a high-definition screen. Thus, the user cannot view the screen or the user can view a distorted screen with noise.